基础振动对转子系统动力特性影响的试验研究

Experimental Investigation on Dynamic Characteristics of Rotor System Subject to Foundation Vibration

为了满足航空发动机转子系统的动力学设计需求,采用试验方法研究基础的振动幅值和振动频率对转子系统横向振动的影响。结果表明,基础振动对转子动力特性的影响具有方向正交性,基础的水平振动仅影响转子的水平振动响应。转子与基础产生振动耦合,其轴心轨迹的形状和大小受基础振动幅值和频率共同影响,转子振动幅值随基础振幅增加而线性增加,随频率的增加呈二次函数增长,振幅比最大可以达到4。由于基础过大的振幅或频率会带来轴心轨迹的复杂变化,导致振动响应过大,在航空发动机的转子动力特性设计中,必须考虑和有效控制基础的振动幅值和频率,以降低转子系统的振动响应。

In order to meet the requirements of dynamic design for rotor system of aero-engine,the effects of the foundation vibration,especially in exciting amplitudes and frequencies,on the transverse vibration characteristics of a rotor system were investigated experimentally. The results show that the impact of the foundation vibration on the dynamics characteristics possesses an orthogonality in direction,suggesting that the vibration of the foundation in horizontal can merely affect the horizontal response of the rotor. Otherwise,coupled vibration happened between the rotor and foundation. Both of amplitudes and frequencies of the foundation excitation have significant influence on the behavior of the rotor including shape and magnitude of orbits. The amplitude of the rotor increases linearly with the amplitude increment of foundation while it increases quadratically as the frequency of the foundation vibration grows. As a result,the amplitude ratio can most reach 4. Considering the intricate changes in shape and sharp augment in rotor amplitude resulting from large foundation vibration,the influence of foundation must be taken into account in the dynamic design for aero-engine rotor system,so as to make sure that the vibration of the rotor stays at a low level.